The present invention concerns the remanufacture of electronic control modules, such as for use with electronically controlled engines. In particular, the invention concerns a system and method for opening a sealed module and resealing the module after servicing the internal components.
Most modern internal combustion engines have some form for electronic controller that governs the operation of the engine. In the case of larger vehicles, a substantial engine control module is provided that performs a wide range of functions. For example, the module provides signals via an electrical harness to various electrical components throughout the engine and vehicle. In addition, the module receives signals from a number of sensors disposed at various locations throughout the engine.
For example, as shown in FIG. 1, an engine control module (ECM) 10 includes a housing 11 with a top mounting boss 12 and side bosses 13 extending therefrom. The mounting bosses provide a means for mounting the ECM 10 within the vehicle or engine compartment. The ECM 10 includes a number of electrical components and microprocessors within the housing 11. A pair of connectors 17 are provided for engaging a pair of cables or harnesses 18, 19. These cables 18, 19 link the electronic and microprocessor components of the ECM 10 to the various sensors and engine control devices.
These electronic control or engine control modules utilize microelectronic components mounted on a substrate. In one type of ECM 10, a circuit board 20 is provided that includes a number of components 21 mounted thereon (see FIG. 2). In one particular approach, the circuit board 20 is formed of a flexible material, such as polyimide. The circuit board 20 is mounted to a rigidizer 15, which is formed of a relatively rigid substrate that is capable of withstanding the harsh environment of the engine. With this ECM, the rigidizer material has properties that allow the rigidizer to be folded or bent. In one example, the rigidizer is formed of aluminum.
One particular rigidizer 15 is shown in FIG. 2. The rigidizer 15 includes a top plate 16A, a bottom plate 16B and an integral intermediate bend region 16C between the two plates. The bottom plate 16B defines a number of connecting holes 22, which receives a number of screws therethrough for attaching the connectors 17 to the outside surface of the bottom plate. A number of slots 23 are formed at the bend region 16C of the circuit board 20 as a bend relief feature and to accommodate a hinge support component of the housing 11, as described herein. The rigidizer 15 also defines certain features for retaining and supporting circuit board 20. For example, the rigidizer defines a sealing or alignment rim 27 around the perimeter of the top plate 16A and bottom plate 16B. The outer perimeter of the circuit board 20 follows the contour of the sealing rim 27. Preferably, the circuit board 20 is engaged to the rigidizer 15 with a compatible adhesive. The sealing rim 27 is offset from the edges of the rigidizer 15 for reasons made clear herein. The rigidizer 15 also defines a plurality of housing mounting holes 25 that are used to receive a like number of screws 26 (FIG. 1) for closing the rigidizer 15 about the housing 11 to form the sealed module 10. A number of mounting boss reliefs 24 can also be defined around the edge of the rigidizer 15 to correspond to the location of the side mounting bosses 13 of the housing 11.
Details of the housing 11 are shown in FIG. 3. Like the rigidizer 15, the housing is preferably formed of a rigid metal, such as aluminum. The housing 11 is generally sized to correspond to half of the rigidizer 15, since the housing is disposed between the top plate 16A and bottom plate 16B. Thus, the features depicted in FIG. 3 appear on both sides of the housing 11. For example, the housing includes an outer rim 30 that follows the outer perimeter of the housing. An inner rim 31 is also formed in the housing offset inward from the outer rim. The inner rim 31 corresponds to the configuration to the sealing rim 27 defined on rigidizer 15.
The housing 11 defines a number of connector holes 37 that align with the corresponding mounting holes 22 in the circuit board 20 and rigidizer 15. A number of mounting holes 38 pass through the housing 11 and are aligned with the housing mounting holes 25 to receive the screws 26. The housing 11 also includes a number of hinge supports 35 that are aligned with the slots 23 formed in the circuit board 20. These hinge supports 35 are preferably rounded and provide a surface about which the bend portion 16C of the rigidizer 16 is folded.
As shown in FIG. 4, the housing 11 is sandwiched between the top plate 16A and the bottom plate 16B of the rigidizer 15. A number of connector mounting screws 39 pass through the mounting holes 37 in the housing 11 and the holes 22 in the bottom plate 16B to engage the connectors 17. In the construction of this module 10, the rigidizer 15 is bent around the housing 11. The rigidizer 15 is configured to essentially sit within the outer rim 30 of the housing, as shown most clearly in FIG. 5. When the rigidizer 15 is bent around the housing 11, the various rims, namely the sealing rim 27 of the rigidizer 15, and the outer and inner rims 30, 31 of the housing 11, define a bead groove 33 that travels around three sides of the perimeter of the module 10. The bead groove 33 need not extend to the bend region 16C of the rigidizer 15, since that side or edge of the module 10 is already closed. Before the top plate 16A and bottom plate 16B of the rigidizer 15 are bent to their final position, an adhesive or sealant bead 40 is applied along the bead groove 33. This sealant bonds the rigidizer 15 to the housing 11. Preferably, the bead material is capable of bonding metal-to-metal, while withstanding the high temperatures experienced in the engine compartment. In one embodiment, the bead is an RTV material.
While the ECM 10 depicted in FIGS. 1-5 provides an environmentally sound and sealed module, difficulties arise when the module must be remanufactured. This remanufacturing process may be required when there is an update to some of the components 21 mounted on the circuit board 20. In other instances, direct diagnosis of the components is necessary, necessitating access to the circuit board 20. In the absence of remanufacturing, the ECM 10 is simply disposed of or scavanged, and replaced with a new module. Of course, this approach unnecessarily wastes resources and can lead to delays where the module is difficult to obtain.
Consequently, there is a need for a system and method that permits the remanufacture of modules, such as the ECM 10 described above. The system and method must be capable of opening the module without disturbing or compromising the rigidizer 15, or the circuit board 20 and its components.